A mode is known that, in a work line comprised of a plurality of operation processes, a robot having a plurality of joints performs a series of operations to receive a workpiece at at least one of the operation processes after an upstream work is finished, and after the work concerned is performed, to send out the workpiece to a downstream side.
Among the plurality of operation processes, it can be considered that the robot performs a process, for example, to take out one workpiece from a container where many workpieces, such as electronic components, are accommodated and to perform a work to the component. Generally, such a process is referred to as “bin picking.” For example, in the following Patent Document 1, a workpiece is placed on a given tray, the workpiece is imaged by a plurality of cameras from a plurality of different angles, and the position of the workpiece is acquired three-dimensionally. The workpiece is recognized by performing a pattern matching using a prestored shape of the workpiece based on information on the acquired workpiece and the robot then takes one workpiece out of the plurality of workpieces accommodated in the tray. Here, if the plurality of workpieces accommodated in the tray overlap with each other, the workpiece recognition may not be able to be performed. In order to avoid such a workpiece overlap, a work to uniformly distribute the workpieces in the tray is carried out by vibrating the tray etc. (e.g., refer to Patent Documents 2 and 3, etc.).